Steam-boiler



(No Model.)

P. J. & F. W. DOLL.

STEAM BOILER.

W/TNESSES: /NVENTOHS A TTOHNEYS.

NUNTTED STATES PATENT OFFICE.

PHILIP J. DOLL AND FRED. W. DOLL, OF LA SALLE, ILLINOIS.

STEAM-BOILER.

SPECFICATONforming part of Letters Patent No. 503,834, dated August 22, 1893. Application November 19, 1892. Serial No. 452,499- (No model.)

To all whom, it may concern.-

' the construction of this class of boilers and produce a boiler which may be very cheaply built, which is extremely durable, which has all the parts subject to great heat arranged below the water line, which is adapted to genof parts, as will be hereinafter described and Y claimed.

Reference is to be had to the accompanying drawings, forming a part of this specilication, in which similar figures of reference indicate corresponding parts in both the the views.

Figure 1 is a central vertical section of the boiler embodying our invention, on the line 1-1 in Fig. 2; and Fig. 2 is a sectional plan on the line 2-2 in Fig. 1.

The boiler is provided with the usual sheet 10 which forms the casing of the boiler and which rests upon a suitable metallic base 11. The boiler has also in its lower end the usual form of fire box 12, having the ordinary door 12:, this fire box being formed by a generally cylindrical sheet 13 which is arranged in the lower portion of the boiler and the lower edge of which is bent outward and bolted firmly to the boiler sheet, as shown at 14, in Fig. 1. This construction we do not claim as part of our invention.

At the top of the fire box is the usual crown sheet 15 which is riveted firmly to the sheet 13, and extending vertically upward from the crown sheet 15 are the tubes 16, which are arranged in the usual way and terminate at their upper ends in a horizontal flue sheet 17 which forms the bottom of the smoke box.

bonnet when it is burned out.

The sides 1S of the smoke box are inclined inwardly, and the smoke box as a whole is thus shaped like the frustum of a cone. The wall 1S terminates at its upper edge in an inwardly extending flange 19 which serves as a support for the conoidal bonnet 20, and this terminates at its upper end in a reduced cylindrical portion 21 to which the stack 22 is secured. The bonnet 20 is made of heavy material, preferably cast iron, so as to prevent the heat from radiating and seriously affecting the inner boiler sheet 23, which sheet is bent into a cylindrical shape, but tapers slightly inward. This sheet is secured to the upper edge of the sides 18 of the flue sheet and smoke box, and the top edge of the sheet 23 is secured to the top 24 of the boiler.

It will be noticed that the smoke box is arranged below the water line, and consequently the flue sheet and the sides of the smoke box can never be burned out, and moreover, the hot products of combustion held in the smoke box assist in generating steam.

The inner sheet 23 of the boiler is expanded toward the top, as described, and this facilitates the forming and free rise of steam in the boiler, as the distance between the lower portion of the sheet 23 and the sheet 10 is greater than the distance between the top portions of said parts. The bonnet 2O rests loosely on the flange 19 so that it may be removed whenever it is necessary, and consequently it is an easy matter to remove the The bonnet being thick does not radiate'much heat, and whatever heat does radiate from the bonnet passes up through theair space between the outer wall of the bonnet and the sheet 23, so that the latter is not aected.

The boiler is provided with the usual trycocks 25 and may be provided with any of the usual accessories..

Having thus described our invention, we claim as new and desire to secure by Letters PatentH- y 1. In a boiler, the combination with the cas ing and a fire box in the lower portion thereof, of a smoke box arranged in the upper part of the casing below the water line, and having inwardly inclined walls, tubes leading from the re box to the smoke box, abonnet above the smoke box, and an inner boiler sheet secured to the top of the casing and to the upof a smoke box having inwardly inclined sides per edge of the smoke box, substantially as andan inwardly extending flange at its top, described. `tubes leading from the fire box to smoke box, 2. In a boiler, the combination with theoasa-conoidal bonnet resting upon the ilange of 5 ing and a. lire box in the lower portion thereof, the smoke box, and an inner boiler sheet ta- 2o of a smoke box arranged below the water line l perng inwardly and secured to the top of the and having inwardly inclined sides,.tubes `casi-ng and to the upper edge of the smoke leading from the fire box to the smoke box', a. box, substantially as herein shown and debonnet removably supported above the smoke scribed.

1o box, and an inner boiler sheet tapering inwardly and secured to the top of the casing and to the upper edge of the smoke box,sub i f stantially as described. ,Y Y f l Witnesses: Y Y 3. In a boiler, the combination with the lcasf ANDREW FUN-K,

I5 ing and a fire box in the lower portion thereof, FRANCIS A. WALKER. W 

